Vibilia gibbosa Bovallius 1887

Vibilia gibbosa Bovallius (Figs 5 & 6)

Vibilia gibbosa Bovallius 1887a: 7. — Bovallius 1887c: 53–54, pl. 8, figs 9–17. Vosseler 1901: 119–120, pl. 10, figs 16–19, pl. 11, figs 1–5. Behning 1913a: 529, 533, fig. 1. Behning 1913b: 215. Stephensen 1918: 36–37, fig. 8. Chevreux & Fage 1925: 384–385, fig. 389. Behning 1927: 115–116, 121 (Table), fig. 1. Pirlot 1929: 93–94. Chevreux 1935: 173. Reid 1955: 14. Hurley 1956: 12. Irie 1959: table 4. Evans 1961: 203. Grice & Hart 1962: 300. Yoo 1971: 50­51, fig. 7: Semenova 1973: 171, fig. 2. Brusca 1981: 18 (key), 39, fig. 4h. Vinogradov et al. 1982: 216– 218, fig. 107. Vinogradov 1990a: 56, 93 (Table). Shih & Chen 1995: 39–40, fig. 18. Zeidler 1998: 34, figs 23–24. Vinogradov 1999: 1179, fig. 4.84. Gasca & Shih 2001: 496 (Table).

Type material

No type material was found at the ZMUC, SMNH or in Uppsala and it thus appears to be lost. However, the description and figures of Bovallius (1887c) are sufficient to distinguish this species. Bovallius (1887a) gives the type locality as “tropical parts of Atlantic”, but later (1887c) is more specific, “ 17°30’S, 2°20’W ” (near St. Helena).

Material examined (33 specimens)

North Atlantic: 1 lot (CMN), 7 lots (USNM), 2 lots (ZMB), 1 lot (ZMH), 3 lots (ZMUC), 27 specimens. North Pacific: 2 lots (CAS), 2 specimens. Tasman Sea: 2 lots (SAMA), 4 specimens.

Diagnosis

Body length up to 8 mm. Antennae 1 as long as head and first pereonite; flagellum oval, slightly more inflated medially, distal margin rounded. Gnathopod 2; carpal process about 0.7x length of propodus. Pereopods 3 & 4; dactylus length about half propodus. Pereopods 5 & 6; dactylus length about 0.3x (or slightly more) propodus. Pereopod 7; basis rectangular, slightly longer than wide, as long as ischium to carpus combined, with slight rounded posterodistal lobe barely overlapping ischium. Lateral corners of last urosomite not produced. Uropod 3; peduncle distinctly longer than rami; sexual dimorphism of endopod not evident. Telson; rounded, almost semi­circular, length about half peduncle of U3.

Remarks

This species is readily distinguished from its congeners by the bulbous nature of the flagellum of the first antennae, in combination with other minor characters. It is most similar to V. propinqua Stebbing, 1888, but in that species the flagellum of antennae 1 is no wider than the peduncular articles, and the structure of pereopod 7 is slightly different. It is also similar to V. jeangerardi Lucas, 1846, but in that species the dactylus of pereopods 3–6 is relatively shorter, especially those of pereopods 5 and 6 (only about 0.7x length propodus). In the shape of antennae 1, V. gibbosa also resembles V. longicarpus Behning, 1913, but that species differs in many respects particularly in the shape of the urosome and gnathopod 2, in which the carpal process is slightly longer than the propodus.

Prior to this study the salp associate for this species was unknown. However, Moira Galbraith (pers. comm.) has recorded it from Salpa fusiformis and S. aspera in the northeastern Pacific.

Distribution

This is an uncommon, widely distributed species in the Atlantic Ocean and the Mediterranean Sea. It is also found in tropical and warm­temperate waters of other oceans, but has not been recorded from the Indian Ocean.